Administrative Services Only plans are the engine behind most self-funded employer health coverage in the US. The structure is deceptively simple: the employer pays claims directly out of its own funds, and a third-party administrator (often a branded arm of a major health insurer like Blue Cross, UnitedHealthcare, Aetna, or Cigna) handles all of the operational work. The employer gets control over plan design and keeps the dollars that would otherwise go to carrier profit margins. In exchange, the employer takes on the financial risk of a bad claims year, which is why ASO plans almost always come with stop-loss insurance attached.
How an ASO Arrangement Actually Works Under an ASO contract, the employer pays the TPA a per-employee-per-month (PEPM) administrative fee and funds a claims account from which the TPA pays provider claims as they come in. The TPA handles the day-to-day: adjudicating claims, applying plan rules, operating the provider network, managing pharmacy benefits (often through a separate PBM contract), and producing IRS and DOL reporting.
Plan members usually don't know the arrangement is self-funded. Their insurance card looks like a standard commercial insurance card, because the TPA is the same name (Blue Cross, etc.) that issues fully insured cards. The distinction matters to the CFO and the benefits team, but not to the employee using the plan.
Who Regulates an ASO Plan? Self-funded ASO plans are regulated primarily under ERISA at the federal level, which preempts most state insurance regulation. That's one of the main reasons employers choose self-funding: it removes state-by-state insurance mandates and produces a more uniform plan across jurisdictions. Fully insured plans are regulated mostly at the state level by state insurance departments, which means state-specific benefit mandates apply.
ASO vs Fully Insured Health Plans The choice between ASO and fully insured comes down to three factors: risk tolerance, claims predictability, and plan design flexibility. Fully insured plans transfer the claims risk to the carrier in exchange for a fixed monthly premium. ASO keeps the risk with the employer, and in a low-claims year the employer keeps what would have been the carrier's underwriting profit.
ASO makes sense once an employer has enough covered lives that claims become statistically predictable (typically 100+ employees, though some brokers recommend self-funding for groups as small as 25 with appropriate stop-loss). Below that threshold, single large claims can swing year-over-year costs too sharply for self-funding to be practical.
Stop-Loss Insurance and Risk Management for ASO Plans Stop-loss insurance is the hedge that makes ASO workable for most employers. It comes in two flavors. Specific stop-loss covers individual high-cost claims above a specified threshold (the "spec deductible," often $25,000 to $500,000 per member). Aggregate stop-loss covers the total claims across the plan exceeding a projected annual ceiling (typically 120-125% of expected claims).
Premiums for stop-loss have risen meaningfully in 2024-2026 as high-cost specialty drugs, cell and gene therapies, and complex medical cases have concentrated risk into fewer claimants. A well-structured stop-loss layer is the difference between a manageable bad year and a budget crisis. See the DOL ERISA guidance for the federal framework that governs self-funded plans.
When an Administrative Services Only Plan Makes Sense ASO fits employers who have enough scale to make claims predictable, enough internal bandwidth (or broker support) to manage the self-funded operations, and enough interest in plan design control to do the work. The typical scenarios: mid-size and large employers looking to reduce total benefit costs, employers with below-average claims experience whose risk-adjusted cost under ASO beats the fully insured premium, and multi-state employers who want a single uniform plan.
The scenarios where ASO doesn't fit: small employers without the statistical scale to absorb variance, employers with highly volatile workforce composition, and employers who lack the broker or benefits expertise to manage the additional complexity. The transition from fully insured to ASO is a year-long project that involves reserve funding, ERISA plan document drafting, and network contract renegotiation. Rushing it typically produces a plan that looks like ASO on paper but is operated like fully insured, which captures none of the savings and most of the risk.
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